The organization of goal-directed action is influenced significantly by the agent's ability to inhibit or gate responses to sensory, motor and cognitive information. Deficits in these central inhibitory mechanisms are manifest in a number of neuropsychiatric syndromes characterized by disorders of 'voluntary' movement, e.g. Parkinson's disease, and intrusive involuntary movement, e.g. Tourette's syndrome and Huntingdon's disease. These cases make it clear that the capacity for goal-directed action is highly adaptive, indeed it is this capacity that allows us and other animals to control the environment in the service of our needs and desires. Nevertheless, although research into the physiological systems that subserve learning processes in humans and other animals has been of ongoing concern to the neuroscience research community, the neural basis of instrumental action is very poorly understood. [unreadable] [unreadable] The broad, long term objective of the current project is, therefore, to understand the neural mechanisms that control the learning and performance of goal directed or instrumental actions. Over the last decade striking advances have been achieved in our understanding of the behavioral determinants of instrumental conditioning in animals. Specifically, instrumental performance has been found to reflect the integration of (i) representations of the relations between an action and its consequences; with (ii) representations of the incentive value of those consequences. Powerful behavioral procedures will be used to focus on the role of cortico-striatal interactions and feedback to cortex via pallidal and limbic structures in processes involved in the representation of the relation between an action and its consequences. In other experiments, the role of parallel interactions between insular cortex and basal forebrain structures in the representation of the incentive or 'goal' value of the instrumental outcome will be assessed. [unreadable] [unreadable]